The invention relates to a plunger type hay baler whose frame can be hitched to a tractor to assure intake and packing of the hay in a pressing channel of the machine during advance of the baler.
Such a baler is known from Patent FR 2 346,963 in which a loading chute connects to the pressing channel while a plunger with alternating movement assures packing of the hay load conveyed by the loading chute. In this baler, the phase of packing the hay load is an important phase of preparing a bale having a desired density and shape. In view of the varieties of hay and the varied shapes of rows, the baler plunger packs successive hay loads whose volume and density are constant. Feeding of the pressing channel under these conditions requires the use of a density measuring system.